1. Field of the Invention
The present invention generally relates to a recording apparatus such as an inkjet printer.
2. Description of the Related Art
In an inkjet-type recording apparatus, ink is discharged from a recording head mounted on a carriage while the carriage moves back and forth in the main-scanning direction, so that ink can be adhered onto a recording medium placed on a platen plate to record a line image (dots) on the recording medium. Further, the recording medium is fed in the sub-scanning direction (perpendicular to the main-scanning direction) using a feeding roller and the like and a recording process in the main-scanning direction is repeated to form an image on the recording medium.
However, in the inkjet-type recording apparatus, there may be a problem where a feeding amount of the recording medium varies when the recording media is fed using a feeding roller depending on installation conditions of the feeding roller, eccentricity level of the feeding roller, a type of the recording medium and the like. When the feeding amount of the recording medium varies, the dots of the image may be formed on the positions which differ from the respective desired positions.
To resolve the problem, in the related art of the present invention, for example, Japanese Patent Application Publication No. 2007-261262 (“Patent Document 1”) discloses a technique in which a test pattern to be formed on a recording medium is recorded. Then, the based on the recorded test pattern, a positional displacement amount in the feeding direction of the recording medium is detected, so that the rotation of the feeding roller is controlled.
However, in a technique such as disclosed in Patent Document 1, if the nozzles to be used for forming the test pattern have a problem due to a missing nozzle, a bent nozzle or the like, an accurate test pattern may not be formed. Further, if the positional displacement amount obtained based on such an inaccurate test pattern is used for controlling (correcting) the rotation of the feeding roller, wrong control may be executed. As a result, accurate control of the rotation of the feeding roller may not be achieved.